A Model for Induction Motors with Non-Uniform Air-Gap

Equations to calculate inductances of induction motors, considering non-uniform air-gap, are proposed. The analyzed air-gap variations are static and dynamic eccentricity and stator slots. The equations for inductance calculation, obtained from the modified winding functions and the energy stored in the air-gap, allow considering the effect of rotor bar skewing. Experimental results that validate the proposed method are presented.Fil: Bossio, Guillermo Rubén. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ingeniería. Grupo de Electrónica Aplicada; ArgentinaFil: de Angelo, Cristian Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ingeniería. Grupo de Electrónica Aplicada; ArgentinaFil: Solsona, Jorge Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; ArgentinaFil: Garcia, Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ingeniería. Grupo de Electrónica Aplicada; ArgentinaFil: Valla, Maria Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales. Universidad Nacional de La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales; Argentin

Detection of hydraulic phenomena in francis turbines with different sensors

Nowadays, hydropower is demanded to provide flexibility and fast response into the electrical grid in order to compensate the non-constant electricity generation of other renewable sources. Hydraulic turbines are therefore demanded to work under o -design conditions more frequently, where di erent complex hydraulic phenomena appear, a ecting the machine stability as well as reducing the useful life of its components. Hence, it is desirable to detect in real-time these hydraulic phenomena to assess the operation of the machine. In this paper, a large medium-head Francis turbine was selected for this purpose. This prototype is instrumented with several sensors such as accelerometers, proximity probes, strain gauges, pressure sensors and a microphone. Results presented in this paper permit knowing which hydraulic phenomenon is detected with every sensor and which signal analysis technique is necessary to use. With this information, monitoring systems can be optimized with the most convenient sensors, locations and signal analysis techniquesPostprint (published version

¿Puede el arte autónomo contener elementos emancipatorios? Reflexiones en torno al debate Adorno-Benjamin y su actualidad para la práctica de la crítica

Fil: García Bossio, María Pilar. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina

Sensor-based optimized control of the full load instability in large hydraulic turbines

Hydropower plants are of paramount importance for the integration of intermittent renewable energy sources in the power grid. In order to match the energy generated and consumed, Large hydraulic turbines have to work under off-design conditions, which may lead to dangerous unstable operating points involving the hydraulic, mechanical and electrical system. Under these conditions, the stability of the grid and the safety of the power plant itself can be compromised. For many Francis Turbines one of these critical points, that usually limits the maximum output power, is the full load instability. Therefore, these machines usually work far away from this unstable point, reducing the effective operating range of the unit. In order to extend the operating range of the machine, working closer to this point with a reasonable safety margin, it is of paramount importance to monitor and to control relevant parameters of the unit, which have to be obtained with an accurate sensor acquisition strategy. Within the framework of a large EU project, field tests in a large Francis Turbine located in Canada (rated power of 444 MW) have been performed. Many different sensors were used to monitor several working parameters of the unit for all its operating range. Particularly for these tests, more than 80 signals, including ten type of different sensors and several operating signals that define the operating point of the unit, were simultaneously acquired. The present study, focuses on the optimization of the acquisition strategy, which includes type, number, location, acquisition frequency of the sensors and corresponding signal analysis to detect the full load instability and to prevent the unit from reaching this point. A systematic approach to determine this strategy has been followed. It has been found that some indicators obtained with different types of sensors are linearly correlated with the oscillating power. The optimized strategy has been determined based on the correlation characteristics (linearity, sensitivity and reactivity), the simplicity of the installation and the acquisition frequency necessary. Finally, an economic and easy implementable protection system based on the resulting optimized acquisition strategy is proposed. This system, which can be used in a generic Francis turbine with a similar full load instability, permits one to extend the operating range of the unit by working close to the instability with a reasonable safety margin.Postprint (published version

Conserving land, protecting water

Water resource management / Water productivity / Water conservation / Recycling / Land management / Soil conservation / Ecosystems / Ecology / Evapotranspiration / Food security / Poverty / River basins / Irrigated farming

Adolescents from low-income sectors: the challenge of studying in a time of digital environments

This paper is about practices and perceptions regarding the study of adolescents from low-income sectors in the City of Buenos Aires. The methodology consisted of 26 in-depth interviews with low-income adolescents and participant observations in twenty cybercafés of the South Area of the City of Buenos Aires. Among the findings, these students highlight that ICTs allow them to handle information in a more agile and entertaining way, more consistent with their daily uses. However, doing research on school content is what students do the least, since adolescents use technology mainly for communicative, social and recreational ends. These adolescents recognise some disadvantages in using ICTs to study: the unreliable information, the difficulty to distinguish which topics related to school content are more appropriate and the disruptive and continuous use of social networks. In this sense, these adolescents tend to have more problems in benefitting from ICTs for academic purposes than other adolescents. While communication and recreational skills tend to be similar, the evaluation of different sources of information and the skill to make complex searches online are usually more strongly developed in adolescents of middle and high-income households. In conclusion, we think it is necessary to take these problems into consideration in the social sciences research of the area and besides when implementing digital literacy programs.Fil: Linne, Joaquín Walter. Universidad de Buenos Aires. Facultad de Ciencias Sociales. Instituto de Investigaciones ; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Does Wheat Cultivar Choice Affect Crop Quality and Soil Microbial Communities in Cropping Systems?

Wheat (Triticum aestivum L.) cultivars may have differential effects on soil microbial communities and the breadmaking quality of harvested grain. We compared six Canadian spring wheat cultivars under organic and conventional management systems for yield, breadmaking quality and soil phospholipid fatty acid analysis (PLFA) profile. Yields were lower, but protein levels were higher in the organic system. Cultivars differed for quality traits, but all cultivars had acceptable levels for processing. There were small differences in PLFA profiles for cultivars in the conventional system, but none in the organic system. More significant correlations between grain quality and PLFA measures were present in the organic system. Protein levels and breadmaking quality at least equal to conventional systems can be achieved in organic systems. Wheat cultivars differed for grain quality in both organic and conventional systems, and culivars altered the soil microbial profile in conventional systems. Microbes may play a greater role in determining crop quality in organic systems than in conventional systems

Trees and water: smallholder agroforestry on irrigated lands in Northern India

Trees / Populus deltoids / Agroforestry / Afforestation / Reforestation / Models / Water use / Water balance / Evapotranspiration / Precipitation / Remote sensing / Irrigation requirements / India

Don’t be stupid : The role of social media policies in journalistic boundary-setting

This document is an Accepted Manuscript of an article published by Taylor & Francis Group in Journalism Studies on 9 May 2018, available online via: https://doi.org/10.1080/1461670X.2018.1467782 Under embargo until 9 November 2019.Social media are now firmly embedded in professional newsrooms, and policies and guidance within these newsrooms have evolved to include social media activities. These policies articulate and expose the underlying assumptions of the role of these new media within the traditional boundaries of the newsroom. Through thematic analysis of the policies of 17 news organizations, this research identifies and explicates the ways in which professional news organizations have moved and reinforced the boundaries of newswork to both include social media, and to bring social media under its control—to the extent of requiring newsworkers to subsume their personal online identities under their professional ones. The research identifies a number of areas of further research, including analysis of compliance with these policies and resistance to them on the part of newsworkers.Peer reviewedFinal Accepted Versio

Undergraduate Commencement Exercises Program, May 23, 1987.

Bryant University Undergraduate Commencement Exercises Program, May 23, 1987